1. Field of the Invention
The present invention relates generally to a system for removing environmentally harmful contaminants from saturated or ground water regions of the soil subsurface. More specifically, the present invention relates to a system which provides supplemental fluids which are either chemical oxidizers or nutrients which promote accelerated bioremediation of targeted contaminants within the subsurface of the soil and groundwater.
2. Description of the Prior Art
The U.S. Government's Department of Defense estimates that 6,045 of their groundwater sites are either under investigation for environmentally harmful contaminants or identified for future cleanup and restoration. Chlorinated solvents are the most prevalent organic contaminants in groundwater. Chlorinated aliphatic hydrocarbons (CAHs), such as trichloroethylene and perchloroethylene, have been found at approximately 80% of all Superfund sites having groundwater contamination and more than 3000 Department of Defense groundwater contaminated sites in the United States. The life-cycle costs to clean up these sites are uncertain, but are likely to exceed several billions of dollars nationally. The Department of Defense (DOD) could spend more than $100 million annually for hydraulic containment at these sites using, for example, pump-and-treat technologies, and estimates of total life-cycle costs exceed $2 billion. Approximately seventy-one percent of these DOD sites are classified as having groundwater contamination.
One of the technologies currently in use to remediate CAHs found in groundwater is In-situ Chemical Oxidation (ISCO). In-situ chemical oxidation utilizes the introduction of chemical oxidants into the soil's subsurface to destroy organic contaminants in soil and groundwater, with the purpose being to reduce the mass, mobility, and/or toxicity of contamination in soil and groundwater. Although the chemistry of in-situ chemical oxidation is relatively simple, the technology is not a simple one to implement. The soil's subsurface environment can be difficult to control, and it can be difficult to get adequate distribution of the oxidants within the soil's subsurface. Current limitations to properly treat groundwater include the difficulty of bringing reactants into contact with contaminants, located in low permeability matrices in which diffusion and mass transfer are minimal.
Accordingly, there is a need for an effective, efficient and economical sparging system which can deliver either chemical oxidizers to promote contaminant destruction or nutrients to the soil's subsurface to promote accelerated bioremediation of targeted contaminants within the subsurface of the soil and groundwater.